Security element, such as a thread, strip and the like, for security documents

ABSTRACT

A security element, such as a thread, strip and the like, for security documents in general, which comprises a flexible backing layer that has, on at least one face, a layer of metallic material provided with regions in which the thickness of the metal is less than 70% and more than 25% of the thickness of the layer of metallic material of the nearby portions, and further comprises a layer of embossed holographic lacquer between the backing layer and the layer of metallic material.

TECHNICAL FIELD

The present invention relates to a security element such as thread,strip, patch and the like for security documents in general.

BACKGROUND ART

As is known, security threads that allow correct interpretation even byvisual inspection, without necessarily resorting to particularinstruments or devices, have already been used in the production ofsecurity documents, such as for example bank notes, certificates,passports and the like.

Among solutions of this kind, mention should be made of a securitythread, disclosed in EP 0 319 157, which is substantially constituted bya strip of plastic material on which a layer of metallic material,generally aluminum, is deposited; areas are provided thereon in whichgraphic markings, text or the like are written in hollow form, sincethey are formed by metal-free regions located so as to maintain themetallic continuity of the thread.

The most widely used solution for-producing this thread is the use ofsystems for demetallizing aluminum vaporized in vacuum on a polyesterfilm.

Over time, it has been found that this type of execution, whichinitially had a good degree of security, can be circumvented, sincecounterfeiters, by virtue of the increased availability of technology,have succeeded in providing very valid simulations by virtue of punchtransfer methods or even by using laser beams for marking.

Another known solution that used this type of thread entailed insertionin the paper with the so-called windowing technique, disclosed forexample in U.S. Pat. No. 4,186,943, which provided for the insertion ofthe strip in the paper with protrusion of the thread in a selected andcontrolled position so as to be able to see all the characteristics ofthe security thread in reflected light in the places where it liesoutside the paper and the texts or graphic markings without metal intransmitted light in the places where the thread is inserted in thepaper, thus achieving a further function for such thread.

In this case also, counterfeiters have been able to simulate the threadsystem by depositing similar materials, by using a punch and/or laserbeam technique.

To increase the degree of security, solutions have already been devisedin which additional security elements were applied to the thread with aholographic technique or the like, but in these solutions the textregion provided in hollow form, or with partial or complete covering ofthe text, as disclosed for example in EP 0 330 733, produced an absenceof holographic detection also on the character or graphic markings, sothat the counterfeiter could still use punch or laser application.

DISCLOSURE OF THE INVENTION

The aim of the invention is to eliminate the drawbacks cited above, byproviding a new type of security element, such as a thread, strip, patchand the like, for security documents in general, that allows to extendconsiderably the degree of protection, combining with conventionalthreads the possibility to have a holographic representation orotherwise a representation that varies the colors that are reflected asa function of the type of light and of the angle with which they arestruck.

Within this aim, an object of the invention is to provide a securityelement in which it is possible to have continuity of the holographiccharacteristics or of the color variation also in the regions where textis provided.

Another object of the present invention is to provide a security elementthat thanks to its particular constructive characteristics is capable ofgiving the greatest assurances of reliability and safety in use.

Another object of the present invention is to provide a securityelement, such as a thread, strip and the like, for security documents ingeneral, that can be obtained easily starting from commonly commerciallyavailable elements and materials and is also competitive from a merelyeconomical standpoint.

This aim and these and other objects that will become better apparenthereinafter are achieved by a security element, such as a thread, stripand the like, for security documents in general, according to theinvention, which comprises a flexible backing layer that has, on atleast one face, a layer of metallic material provided with regions inwhich the thickness of the metal is less than 70% and more than 25% ofthe thickness of the layer of metallic material of the nearby portions,characterized in that it comprises a layer of embossed holographiclacquer.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will becomebetter apparent from the description of a preferred but not exclusiveembodiment of a security element, such as a thread, strip and the like,for security documents in general, illustrated by way of nonlimitingexample in the accompanying drawings, wherein:

FIG. 1 is a schematic view of the security element according to theinvention, in the form of a strip;

FIG. 2 is a layered view of the security element of FIG. 1;

FIG. 3 is a layered view of a security element with a layer ofcolor-shifting material;

FIG. 4 is a schematic view showing an embedded thread of the documentthat cannot be detected in reflected light;

FIG. 5 is a schematic view, showing the thread that is detectable intransmitted light.

WAYS TO CARRYING OUT THE INVENTION

With reference to the figures, the security element, such as a thread,strip, patch and the like, for security documents in general, comprisesa flexible backing layer, designated by the reference numeral 1, whichis advantageously made of polyester according to conventional methods.

A layer of metallic material 2 is provided on the backing layer 1, andon said layer there are regions, schematically designated by thereference numeral 3, in which the thickness of the metal is less than70% and more than 25% of the thickness of the layer of metallic materialof the nearby portions, i.e., the thickness is therefore comprisedbetween 25 and 70% of the thickness of the layer of metallic material ofthe nearby portions, as shown in WO 2004/014665 A1, which is assumedincluded herein by reference.

Explicitly with reference to FIGS. 1 and 2, an important particularityof the invention consists in that a holographic lacquer, designated bythe reference numeral 5, is preferably interposed between the backinglayer 1 and the layer of metallic material 2, and is embossed so as toprovide a holographic representation or optionally an exelgram, apixelgram, an e-beam, a kinegram and so forth; although the best resultshave been achieved with the solution described above, the holographiclacquer can also be arranged on top of the metallic layer or on theother face of the backing layer.

The holographic lacquer 5 is covered completely by the aluminum, whichis deposited in vacuum and, after providing the regions 3, a continuityof the hologram is obtained even in the regions 3 that show graphicmarkings, designs, letters and so forth, differently from the solutionsof the background art; which provided an interruption of the hologram atthe recessed regions that constituted the text, since the metallic layerwas not present in these regions.

With the embodiment described above, by using a layer that has metalliccontinuity on its entire surface it is possible to combine thepossibility to detect the reduced-thickness regions that in practiceconstitute the recessed lettering with the additional security thatarises from the presence of the hologram, which has continuity on thevarious thicknesses of metal, and accordingly a variation of theholographic representation is obtained while maintaining its continuity.

According to what is shown in FIGS. 3 to 5, the security element isagain constituted with the base layer, designated by the referencenumeral 1, and with the layer of metallic material 2 provided with theregions 3, in a manner fully similar to what has been described earlier.

The difference arises from the fact that there is a layer of material 10that shifts color depending on the type of light and on the angle ofincidence of the light; the color-shifting layer 10 is provided forexample by a fluorescent ink or color-shifting ink that allows to havecolor-shifting areas in a parallel and/or alternating manner and in anycase in register with the regions 3 that have a different thickness ofmetal; the color-shifting layer can optionally have a solid background.

Furthermore, with the thread inserted in the document, generallydesignated by the reference numeral 20, the thread is not visible inreflected light, as shown in FIG. 4, and is instead visible intransmitted light and, if viewed from the side provided with themetallic layer, the typical characteristic of the metallic layer iscombined with the color variability that is provided by the layer 10made of a material that has particular color properties.

It should be noted that the thread can be embedded completely in thedocument or inserted with the so-called “windowing” technique. Thesecurity element, once inserted in the document is always visible atopenings provided on at least one face of the document.

The layer 10 can be arranged in the most disparate manner, i.e., it canbe arranged so as to have portions that are alternated with the regions3 or optionally continuously and in any case in any type of applicationthat allows to define a constant relation between the presence of thelayer and the regions 3.

Another possibility to increase the security characteristics is toprovide magnetic elements in register with the regions 3; said magneticelements can be of different kinds and can be for example of the typeshown in EP 310707.

From the above description it is thus evident that the inventionachieves the intended aim and objects, and in particular the fact isstressed that a security element, such as a thread, strip and the likeis provided which allows, by using a continuous metallic layer, to havecontinuity in the holographic representation and continuity even if inksthat produce color-shifting effects are used, while having adifferentiation of the color aspect depending on the different thicknessof the metallic layer.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims.

All the details may further be modified according to requirements.

The disclosures in Italian Patent Application No. MI2003A000929 fromwhich this application claims priority are incorporated herein byreference.

1. A security element for security documents, comprising a flexiblebacking layer that has, on at least one face, a layer of metallicmaterial provided with regions in which a thickness of the metal is lessthan 70% and more than 25% of a thickness of the layer of metallicmaterial of all other portions of the layer; and a layer of embossedholographic lacquer.
 2. The security element according to claim 1,wherein said layer of holographic lacquer is ranged between said backinglayer and said layer of metallic material.
 3. The security elementaccording to claim 1, wherein said layer of holographic lacquer isarranged on top of said layer of metallic material.
 4. The securityelement according to claim 1, wherein said layer of holographic lacqueris arranged on said backing layer, on the opposite face with respect tosaid metallic layer.
 5. The security element according to claim 1,inserted in a document, and which is always visible at openings providedon at least one face of said document.
 6. The security clement accordingto claim 1, comprising magnetic elements in register with said regions.7. The security element according to claim 6, wherein said magneticelements provide a magnetically detectable code.
 8. A security elementfor security documents, comprising a flexible backing layer that has, onat least one face, a layer of metallic material provided with regions inwhich a thickness of the metal is less than 70% and more than 25% of athickness of the layer of metallic material of all other portions of thelayer, and further comprising, on said backing layer, a layer ofmaterial that shifts color under light according to the type of lightand angle of incidence of the light, said layer of color-shiftingmaterial being in register with said regions.
 9. The security elementaccording to claim 8, wherein a holographic representation visible onsaid metallic layer is different between said regions and the remainingpart.
 10. The security element according to claim 8, wherein said layerof color-shifting material is applied with a solid background.
 11. Thesecurity element according to claim 8, wherein said layer ofcolor-shifting material is arranged between said backing layer and saidlayer of metallic material.
 12. The security element according to claim8, wherein said layer of color-shifting material is arranged above saidmetallic layer.
 13. The security element according to claim 8, whereinsaid layer of color-shifting material is arranged on said backing layer,on the opposite face with respect to said metallic layer.
 14. Thesecurity element according to claim 8, wherein said layer ofcolor-shifting material is constituted by a fluorescent ink.
 15. Thesecurity element according to claim 8, wherein said layer ofcolor-shifting material is constituted by a layer of color-changing ink.16. The security element according to claim 8, wherein said layer ofcolor-shifting material is arranged so as to be parallel and/oralternated with respect to said regions.
 17. The security elementaccording to claim 8, wherein said security element, once inserted inthe document, is invisible in reflected light and is visible intransmitted light.
 18. A document, comprising a security element as setforth in claim 8.